Refrigerating system



Jan. 10, 1939. c. w. voLLMA'NN 3 2,143,637

REFRIGERATING SYS TEM Filed May 12, 1937 Illllllll vllllllllll I VENTOR c wvoLLMANN ATTORN EY nagaat t io, 1939 STATES PATENT. OFFRE REFRIGERATING SYSTEM Carl W.' Vollmann, Montreal, Quebec, ApplieationMay 12. y11.937, Serial No.. 142,21@ 2 Claims. (Cl. 286-19) This invention relates to compressors for refrigerating machines and particularly to improved means for cooling the piston rod and preventing overheating and destruction of the piston rod packing.

According to this invention the stuing box is provided with spaced inner andouter chambers surrounding the piston rod passing therethrough,

each chamber being located between sections of packing material.. The outer chamber is suitably supplied with lubricating oil to provide an oil seal and to ensure adequate lubrication of the piston rod. The inner chamber is connected to the high pressure side of the refrigerating system so that, through the manipulation of a suitable valve, a small amount of the liquid refrigerant may be supplied to said chamber and brought into direct cooling contact with the outer 'surface of the piston rod. The innerl chamber serves as a small expansion chamber in which the expansion of the liquid refrigerant in direct contact with the surface of the piston rod has a very substantial cooling eifect and prevents overheating and destruction of the packing.

Another advantage resulting from this method of cooling the piston rod is that the oil supplied to the outer chamber retains its lubricating qualities for a longer period and is more effective in reducing friction and prolonging the life of the piston rod and packing.

in the preferred embodiment of this invention the liquid refrigerant employed for cooling the piston rod is supplied to the inner chamber of the stumng box through a valve controlled pipe leading from the high pressure side of the refrigerating system, said pipe being preferably connected to the line leading from the liquid receiver to the refrigerating or expansion coil of the refrigerant circulating system. The liquid refrigerant, on entering vthe inner chamber of the stulng box, vaporizes or expands in direct cooling contact with the surface of the piston rod and is then withdrawn from said chamber through a suction pipe connected to the low pressure side of the refrigerating system. This last mentioned pipe may be connected to the suction line of the refrigerating system (in the case of single stage compression) or it may be connected to the intere mediate pressure line where multi-stage compression is employed.

Proceeding now to a 'more detailed description reference will be had to the accompanying drawing, in whichf Figure 1 is a view partly in side elevation and vpartly in vertical section of a horizontal comoil under a pressure greater than the suction pressor equipped with a stuffing box designed in accordance with this invention.

' Figure 2 is an enlarged vertical sectional viewl Y of the stulng box.

In the construction shown in Figs. 1 and 2, 5 designates the cylinder of a double acting compressor provided with a stumng box 6 through lll which the piston rod 'i passes. The inner and outer chambers provided in accordance with this invention are respectively indicated at B and 9; 'I'he chamber 8 is located inwardly of the chamber 9 and presents inner .and outer channels l5 formed by the sides of an H-shaped metal ring Il) `interposed between the packing rings Il and the intermediate packing rings i2, the two channels being in communication with each other through connecting passages Illa. formed in the w web portion of the metal ring.l Liquid refrigerant is supplied to the inlet i3 of chamber 8 through a supplypipe It equipped with a valve i6. Pipe I5 is connected to the high pressure side of theA refrigerating system at any suitable point between the liquid receiver and the expansion coil of said system. Pipe I5, may, for example, be a branch connection from the line il through which the liquid refrigerant is passed from the liquid receiver to the refrigerant coil of the system. The valve i6 enables the supply of liquid refrigerant through the pipe i5 to be regulated in accordance with requirements.

As the liquid refrigerant enters chamber through the inlet i3 it is sprayed inwardly 35 through the passages Illa and expands in direct cooling contact with the outer surface of the piston rod l. The refrigerant is `then conducted from chamber t tothe low pressure orsuction side i8 of the refrigerating system through the pipe line it.

The oil sealing chamber 9 also presents inner and outer annular channels formed between the sides of an H-shaped metal ring 2l interposed between the intermediate packing rings I2 and: the outer packing rings 22, said channels communicating with each other through suitable opening lla formed in the web portion of ring 2i. The channels and communicating passages of the oil chamber 9 are-maintained fllled with pressure of the compressor. The oil is supplied to chamber 9 through a pipe 24 leading from the bottom of an oil reservoir 25 in which the oil level is maintained at a suitable height to give 2 the requisite pressure in chamber 9. Ilhe` oil may be supplied to the reservoir 25 through a top filling opening closed by the removable cover 26 or it may be pumped into the reservoir through a supply line 21 which connects with the pipe 2l as indicated at 28. The space in the oil reservoir above the oil level is connected to the suction line oil chamber 9 is equal to the suction pressure of the compressor-plus the head pressure of the oil in the standpipe 24A and the reservoir 25.

Since the oil pressure in chamber 9 is always higher than the suction pressure of the compressor it is manifestly impossible for the gaseous refrigerant to leak past this chamber.

The pipe lines 24, 2l and 29 are provided with suitable shut oil' valves indicated at3l, 32 and 33.

Fig. 3 4shows the application of the same invention to a vertical type compressor. vWhile this figure does not show the pipes I5, I9 and 24 connected as in Fig. 1, it will be understood that this would be the case in actual practice.

In some cases the reservoir 25 and the pipe connection 29 are omitted and the oil is delivered directlyto the chamber 8 and maintained at a suitable pressure.

Having thus described my invention, what claim 1s:- V 1 1. In a'. refrigerating system, the combination with the cylinder and piston rod of a reciprocatnthrough the stuillng box, each of said chambers being located between sections of packing material surrounding the piston rod, means for maintaining the outer chamber iled with lubricating oil under a pressure higher than the suction pressure of the compressor, means :for conducting liquid refrigerant from the high pressure side of the refrigerating system directly to the interior of said inner chamber so that the liquid refrigerant expands lin said chamber in direct cooling contact with the piston rod and a return connection through which the expanded refrigerant is immediately passed from said inner chamber back to the low pressure side of the refrigerating system, said return connection being at all times in open communication with said expansion chamber.

2. In a. refrigeratlng system, the combination with the cylinder and piston rod of a reciprocating compressor, of a stuilng box provided with inner and outer non-communicating chambers surrounding the portion of the piston rod passing through the'stufng box, each of said chambers being located between sections of packing material surrounding the piston rod, an oil reservoir mounted above the stuiling box, an cil pipe leading from the bottom of the reservoir to the outer chamber of the stumng box, a liquid refrigerant supply pipe affording a. direct connection between the high pressure side of the refrigerant circulating system andthe interior of'the inner chamber of the stuffing box, af refrigerant ,return pipe connecting said irmer chamber of the stuiiing box to the low pressure side of the refrigerant circulating system, said refrigerant return pipe being always in open communication with said 35 inner chamber and a valve pipe connection between the upper end of the oil\reservoir and said refrigerant return connection.

' CARL W. VOLIMANN. 

